U.S. patent application number 13/663599 was filed with the patent office on 2013-09-19 for power management circuit and electronic device.
The applicant listed for this patent is HAI-LONG CHENG, XUE-BING DENG, XIN-PING LI, XIAO-HUI MA, TAO WANG. Invention is credited to HAI-LONG CHENG, XUE-BING DENG, XIN-PING LI, XIAO-HUI MA, TAO WANG.
Application Number | 20130241295 13/663599 |
Document ID | / |
Family ID | 47844075 |
Filed Date | 2013-09-19 |
United States Patent
Application |
20130241295 |
Kind Code |
A1 |
CHENG; HAI-LONG ; et
al. |
September 19, 2013 |
POWER MANAGEMENT CIRCUIT AND ELECTRONIC DEVICE
Abstract
A power source includes a first power terminal for outputting a
first supply voltage. A power management circuit includes a pulse
width modulation unit having an input power terminal, a first
switch unit capable of being turned on to establish an electrical
connection between the first power terminal and the input power
terminal or being turned off to cut off the electrical connection,
a storage unit. The input power terminal receives the first supply
voltage from the first power terminal when the first switch unit is
turned on, the pulse width modulation unit is powered by the first
supply voltage to generate a pulse voltage at the output terminal.
The storage unit receives the first supply voltage to store energy
when the pulse voltage is in a first level, and releases energy to
generate an operating voltage for powering the load when the pulse
voltage is in a second level.
Inventors: |
CHENG; HAI-LONG; (Shenzhen
City, CN) ; WANG; TAO; (Shenzhen City, CN) ;
DENG; XUE-BING; (Shenzhen City, CN) ; MA;
XIAO-HUI; (Shenzhen City, CN) ; LI; XIN-PING;
(Shenzhen City, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CHENG; HAI-LONG
WANG; TAO
DENG; XUE-BING
MA; XIAO-HUI
LI; XIN-PING |
Shenzhen City
Shenzhen City
Shenzhen City
Shenzhen City
Shenzhen City |
|
CN
CN
CN
CN
CN |
|
|
Family ID: |
47844075 |
Appl. No.: |
13/663599 |
Filed: |
October 30, 2012 |
Current U.S.
Class: |
307/80 ;
323/282 |
Current CPC
Class: |
H02J 9/06 20130101 |
Class at
Publication: |
307/80 ;
323/282 |
International
Class: |
G05F 1/10 20060101
G05F001/10; H02J 4/00 20060101 H02J004/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 13, 2012 |
CN |
201210064645.2 |
Claims
1. A power management circuit connected between a power source and
a load, the power source comprising a first power terminal for
outputting a first supply voltage; the power management circuit
comprising: a pulse width modulation unit having an input power
terminal and an output terminal; a first switch unit capable of
being turned on to establish a first electrical connection between
the first power terminal and the input power terminal or being
turned off to cut off the first electrical connection; and a
storage unit connected between the input power terminal and the
output terminal; wherein the input power terminal receives the
first supply voltage from the first power terminal when the first
switch unit is turned on, the pulse width modulation unit is
powered by the first supply voltage to generate a pulse voltage at
the output terminal; the storage unit receives the first supply
voltage to store energy when the pulse voltage is in a first level,
and releases energy to generate an operating voltage at the output
terminal when the pulse voltage is in a second level; the operating
voltage powers the load.
2. The power management circuit of claim 1, further comprising: a
first sampling unit, wherein the first sampling unit samples the
operating voltage to generate a sampling voltage, the pulse width
modulation unit adjusts a duty cycle of the pulse voltage according
to the sampling voltage.
3. The power management circuit of claim 2, wherein when the
sampling voltage is larger than a threshold voltage, the pulse
width modulation unit decreases the duty cycle; when the sampling
voltage is smaller than the threshold voltage, the pulse width
modulation unit increases the duty cycle.
4. The power management circuit of claim 1, wherein the storage
unit comprises an inductor, one end of the inductor is connected to
the input power terminal, and the other end of the inductor is
connected to the output terminal.
5. The power management circuit of claim 1, wherein the storage
unit comprises a capacitor, one end of the capacitor is connected
to the input power terminal, and the other end of the capacitor is
connected to the output terminal.
6. The power management circuit of claim 1, wherein the first level
is a low level, the second level is a high level.
7. The power management circuit of claim 1, wherein the power
source further comprises a second power terminal for outputting a
second supply voltage; when the first power terminal outputs the
first supply voltage, the second power terminal stops outputting
the second supply voltage; when the second power terminal outputs
the second supply voltage, the first power terminal stops
outputting the first supply voltage; the power management circuit
further comprises a voltage reduction unit and a second switch unit
capable of being turned on to establish a second electrical
connection between the second power terminal and the voltage
reduction unit or being turned off to cut off the second electrical
connection; the voltage reduction unit receives the second supply
voltage from the second power terminal through the second switch
unit when the second switch unit is turned on, reduces the second
supply voltage, and provides the reduced second supply voltage to
the input power terminal of the pulse width modulation unit through
the first switch unit when the first switch unit is turned on; the
pulse width modulation unit is powered by the reduced second supply
voltage to generate the pulse voltage at the output terminal.
8. The power management circuit of claim 7, further comprising a
second diode, wherein the power source comprises a first power
supply for outputting the first supply voltage, a second power
supply for outputting the second supply voltage, a transistor, and
a first diode; the gate of the transistor is connected to the
second power supply, the drain of the transistor is connected to
the first power supply, the source of the transistor is connected
to a cathode of the second diode and the first switch unit, an
anode of the second diode is connected to the voltage reduction
unit; an anode of the first diode is connected to the drain of the
transistor, a cathode of the first diode is connected to the source
of the transistor; the source of the transistor receives the
reduced second supply voltage when the second switch unit is turned
on, the reduced second supply voltage is larger than the first
supply voltage, thus the transistor is turned off and the first
diode is reverse-biased.
9. The power management circuit of claim 7, wherein the first
switch unit and second switch unit are simultaneously turned on or
turned off in response to an external control signal.
10. An electronic device, comprising: a power source comprising a
first power terminal for outputting a first supply voltage; a load;
and a power management circuit connected between the power source
and the load; the power management circuit comprising: a pulse
width modulation unit having an input power terminal and an output
terminal; a first switch unit capable of being turned on to
establish a first electrical connection between the first power
terminal and the input power terminal or being turned off to cut
off the first electrical connection; and a storage unit connected
between the input power terminal and the output terminal; wherein
the input power terminal receives the first supply voltage from the
first power terminal when the first switch unit is turned on, the
pulse width modulation unit is powered by the first supply voltage
to generate a pulse voltage at the output terminal; the storage
unit receives the first supply voltage to store energy when the
pulse voltage is in a first level, and releases energy to generate
an operating voltage at the output terminal when the pulse voltage
is in a second level; the operating voltage powers the load.
11. The electronic device of claim 10, further comprising: a first
sampling unit, wherein the first sampling unit samples the
operating voltage to generate a sampling voltage, the pulse width
modulation unit adjusts a duty cycle of the pulse voltage according
to the sampling voltage.
12. The electronic device of claim 11, wherein when the sampling
voltage is larger than a threshold voltage, the pulse width
modulation unit decreases the duty cycle; when the sampling voltage
is smaller than the threshold voltage, the pulse width modulation
unit increases the duty cycle.
13. The electronic device of claim 10, wherein the storage unit
comprises an inductor, one end of the inductor is connected to the
input power terminal, and the other end of the inductor is
connected to the output terminal.
14. The electronic device of claim 10, wherein the storage unit
comprises a capacitor, one end of the capacitor is connected to the
input power terminal, and the other end of the capacitor is
connected to the output terminal.
15. The electronic device of claim 10, wherein the power source
further comprises a second power terminal for outputting a second
supply voltage; when the first power terminal outputs the first
supply voltage, the second power terminal stops outputting the
second supply voltage; when the second power terminal outputs the
second supply voltage, the first power terminal stops outputting
the first supply voltage; the power management circuit further
comprises a voltage reduction unit and a second switch unit capable
of being turned on to establish a second electrical connection
between the second power terminal and the voltage reduction unit or
being turned off to cut off the second electrical connection; the
voltage reduction unit receives the second supply voltage from the
second power terminal through the second switch unit when the
second switch unit is turned on, reduces the second supply voltage,
and provides the reduced second supply voltage to the input power
terminal of the pulse width modulation unit through the first
switch unit when the first switch unit is turned on; the pulse
width modulation unit is powered by the reduced second supply
voltage to generate the pulse voltage at the output terminal.
16. The electronic device of claim 15, wherein the storage unit
receives the reduced second supply voltage to store energy when the
pulse voltage is in the first level, and releases energy to
generate the operating voltage at the output terminal when the
pulse voltage is in the second level.
17. The electronic device of claim 15, wherein the power management
circuit further comprises a second diode, the power source
comprises a first power supply for outputting the first supply
voltage, a second power supply for outputting the second supply
voltage, a transistor, and a first diode; the gate of the
transistor is connected to the second power supply, the drain of
the transistor is connected to the first power supply, the source
of the transistor is connected to a cathode of the second diode and
the first switch unit, an anode of the second diode is connected to
the voltage reduction unit; an anode of the first diode is
connected to the drain of the transistor, a cathode of the first
diode is connected to the source of the transistor; the source of
the transistor receives the reduced second supply voltage when the
second switch unit is turned on, the reduced second supply voltage
is larger than the first supply voltage, thus the transistor is
turned off and the first diode is reverse-biased.
18. The electronic device of claim 15, wherein the first switch
unit and second switch unit are simultaneously turned on or turned
off in response to an external control signal.
19. The electronic device of claim 17, wherein the transistor is a
PMOS transistor.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The disclosed embodiments relate to a power management
circuit and an electronic device.
[0003] 2. Description of Related Art
[0004] The power management circuit is widely used in electronic
devices. The power management circuit is connected between a power
source and a load, the power management circuit receives a supply
voltage from the power source and provides an operation voltage to
the load in response to an external control signal. The power
management circuit has a feedback terminal, a sampling circuit
samples the operation voltage to generate a sampling voltage and
outputs the sampling voltage to the feedback terminal. The power
management circuit adjusts the operation voltage according to the
sampling voltage.
[0005] However, the adjustment of the power management circuit is
limited, when the supply voltage is suddenly reduced, the operation
voltage is also reduced. Therefore, the reduced operation voltage
may not be enough to power the load.
[0006] Therefore, there is room for improvement in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Many aspects of the embodiments can be better understood
with reference to the following drawings. The components in the
drawings are not necessarily drawn to scale, the emphasis instead
being placed upon clearly illustrating the principles of the
present embodiments. Moreover, in the drawings, like reference
numerals designate corresponding parts throughout two views.
[0008] FIG. 1 is a block diagram of an electronic device in
accordance with one embodiment.
[0009] FIG. 2 is a circuit diagram of the electronic device of FIG.
1 in accordance with one embodiment.
DETAILED DESCRIPTION
[0010] Referring to FIG. 1, an electronic device 900 includes a
power source 100, a load 300, and a power management circuit 200
connected between the power source 100 and the load 300. The power
source 100 includes a first power supply 10, a second power supply
12 (see FIG. 2), a first power terminal 101, and a second power
terminal 102. The first power supply 10 outputs a first supply
voltage through the first power terminal 101, the second power
supply 12 outputs a second supply voltage through the second power
terminal 102. When the first power terminal 101 outputs the first
supply voltage, the second power terminal 102 stops outputting the
second supply voltage; when the second power terminal 102 outputs
the second supply voltage, the first power terminal 101 stops
outputting the first supply voltage.
[0011] Firstly, we describe a first situation when the first power
terminal 101 outputs the first supply voltage and the second power
terminal 102 stops outputting the second supply voltage. The power
management circuit 200 includes a first switch unit 22, a pulse
width modulation (PWM) unit 24 having an input power terminal 240
and an output terminal 242, a storage unit 25, and a first sampling
unit 26. The first switch unit 22 is capable of being turned on to
establish a first electrical connection between the first power
terminal 101 and the input power terminal 240 or being turned off
to cut off the first electrical connection. In this embodiment, the
first switch unit 22 is turned on or turned off in response to an
external control signal.
[0012] The input power terminal 240 receives the first supply
voltage from the first power terminal 101 when the first switch
unit 22 is turned on, thus the pulse width modulation unit 24 is
powered by the first supply voltage to generate a pulse voltage at
the output terminal 242. The storage unit 25 is connected between
the input power terminal 240 and the output terminal 242. The
storage unit 25 receives the first supply voltage to store energy
when the pulse voltage is in a first level, and releases energy to
generate an operating voltage at the output terminal 242 when the
pulse voltage is in a second level; the operating voltage powers
the load 300.
[0013] In this embodiment, the first level is a low level, the
second level is a high level; furthermore, when the pulse voltage
is in the first level, the pulse voltage is zero volts, when the
pulse voltage is in the second level, the pulse voltage is equal to
the first supply voltage and the operating voltage is equal to two
times the first supply voltage.
[0014] The first sampling unit 26 samples the operating voltage to
generate a sampling voltage, the pulse width modulation unit 24
adjusts a duty cycle of the pulse voltage according to the sampling
voltage. In detail, when the sampling voltage is larger than a
threshold voltage, the pulse width modulation unit 24 decreases the
duty cycle; when the sampling voltage is smaller than the threshold
voltage, the pulse width modulation unit 24 increases the duty
cycle. Therefore, the operating voltage keeps stable.
[0015] Secondly, we describe a second situation when the second
power terminal 102 outputs the second supply voltage, the first
power terminal 101 stops outputting the first supply voltage. The
power management circuit 200 further includes a second switch unit
28, a voltage reduction unit 30, and a second sampling unit 32.
[0016] The second switch unit 28 is connected between the second
power terminal 102 and the voltage reduction unit 30. The second
switch unit 28 is capable of being turned on to establish a second
electrical connection between the second power terminal 102 and the
voltage reduction unit 30 or being turned off to cut off the second
electrical connection. In this embodiment, the first switch unit 22
and second switch unit 28 are simultaneously turned on or turned
off in response to the external control signal.
[0017] The voltage reduction unit 30 receives the second supply
voltage from the second power terminal 102 through the second
switch unit 28 when the second switch unit 28 is turned on, reduces
the second supply voltage, and provides the reduced second supply
voltage to the input power terminal 240 of the pulse width
modulation unit 24 through the first switch unit 22 when the first
switch unit 22 is turned on. The pulse width modulation unit 24 is
powered by the reduced second supply voltage to generate the pulse
voltage at the output terminal 242. Therefore, the storage unit 25
receives the reduced second supply voltage to store energy when the
pulse voltage is in the first level, and releases energy to
generate the operating voltage at the output terminal 242 when the
pulse voltage is in the second level.
[0018] Second sampling unit 32 samples the reduced second supply
voltage to generate a sampling signal, the voltage reduction unit
30 adjusts the reduced second supply voltage according to the
sampling signal, therefore keeping the reduced second supply
voltage stable.
[0019] Referring to FIG. 2, the power management unit 200 further
includes a second diode D2. The power source 100 comprises a first
power supply 10 for outputting the first supply voltage, a second
power supply 12 outputting the second supply voltage, a transistor
Q1 and a first diode D1. The gate of the transistor Q1 is connected
to the second power supply 12, the drain of the transistor Q1 is
connected to the first power supply 10, the source of the
transistor Q1 is connected to a cathode of the second diode D2 and
the first switch unit 22, and an anode of the second diode D2 is
connected to the voltage reduction unit 30. An anode of the first
diode D1 is connected to the drain of the transistor Q1, a cathode
of the first diode D1 is connected to the source of the transistor
Q1.
[0020] The source of the transistor Q1 receives the reduced second
supply voltage from the voltage reduction unit 30 when the second
switch unit 28 is turned on, the reduced second supply voltage is
larger than the first supply voltage, thus the transistor Q1 is
turned off and the first diode D1 is reverse-biased; therefore, the
first power terminal 101 stops outputting the first supply voltage
and the second power terminal 102 outputs the second supply
voltage. When the second power supply 12 stops outputting the
second supply voltage, the transistor Q1 is turned on and the first
diode D1 is forward-biased, therefore the first power terminal 101
outputs the first supply voltage and the second power terminal 102
stops outputting the second supply voltage.
[0021] In this embodiment, the first power supply 10 is a battery,
the second power supply 12 is an adaptor for converting an AC
voltage (for example, 220 volts) to a DC voltage, the DC voltage is
equal to the second supply voltage.
[0022] The storage unit 25 comprises an inductor L1, one end of the
inductor L1 is connected to the input power terminal 240, and the
other end of the inductor L1 is connected to the output terminal
242. In other embodiments, the storage unit 25 comprises a
capacitor, one end of the capacitor is connected to the input power
terminal 240, and the other end of the capacitor is connected to
the output terminal 242.
[0023] In the electronic device 900, when the first supply voltage
or the second supply voltage is suddenly increased, because the
storage unit 25 stores energy when the pulse voltage is in the low
level and release energy when the pulse voltage is in the high
level, the operation voltage will still power the load 300.
[0024] Alternative embodiments will become apparent to those
skilled in the art without departing from the spirit and scope of
what is claimed. Accordingly, the present disclosure should not be
deemed to be limited to the above detailed description, but rather
only by the claims that follow and the equivalents thereof.
* * * * *